Influence of Mo diffusion on the thermal behavior of TBCs on Ni₃Al based alloy IC-6

Conventional two-layered structure thermal barrier coatings (TBCs) were prepared onto γ′-Ni₃Al based alloy IC-6 by electron beam physical vapor deposition (EB-PVD). Isothermal oxidation and thermal cycling texts were carried out to investigate the effect of Mo contents at the interface between bond coat and ceramic top coat caused by diffusion. It has been found that the alloy coated with TBCs presented the lowest oxidation weight gain value for the reason that the ceramic top coat in TBC system can effectively stop Mo oxides evaporating. The life time of TBCs has close relation with Mo content at the interface between the bond coat and top coat. Spallation of ceramic top coat occurred during thermal cyclic testing when Mo atoms accumulated at the interface up to certain amount to decline the combination between the bond coat and top coat.